Remote Monitoring of Weapons Components

Los Alamos National Laboratory has developed several techniques for continuously monitoring sensitive materials stored in vaults. These techniques are used in a layered approach to safeguards. The first layer consists of monitors that are strategically placed to monitor the passage of radioactive material into and out of the area. The second layer contains area radiation or volume motion monitors. An array of neutron detectors is installed, for example, on the ceiling of the storage area to monitor the neutron field in a vault produced by a particular geometric configuration of bulk plutonium. Video imaging is a second technique to detect changes or movement in a volume of space. The video image is digitized and compared with a previous digitized image to look for changes in the image. The third layer of safeguards is a network of item monitors for each individual item or a small subset of items. Each monitor contains two independent detectors, for example, a relative mass sensor and a photon detector. When both sensors detect a change simultaneously, there has been movement of the container. Under current regulations, successful application of this strategy can significantly reduce the nuclear material physical inventory requirements.